Magneto



June 5, 1945. J R FRE| 2,377,620

MAGNETO Filed Feb. 12, 1942 '5 Sheet s-Sheet 1 INVENTOR AMMM ATTORNEYJune 1945. J. R. FREI 2,377,620

MAGNETO Filed Feb. 12, 1942 5 Sheets-Sheet 2 BY WP. 5

ATTORNEY June 9 5- J. R. FR'EI 2,377,620

MAGNETO Filed Feb. 12, 1942 5 Sheets-Sheet 3 INVENTOR K a f TORNEYPatented June 5, 1945 MAGNETO Jakob It. Frei, Sidney, N. Y., assignor toBendix Aviation Corporation, South Bend, Ind., a corporation of,Delaware Application February 12,1942, Serial No. 450,554

I 18 Claims.

This invention relates to ignition apparatus and more particularly tocurrent generating means. I

One of the objects of the present invention is to provide a novelmagneto generator adapted for use in the ignition system of an internalcombustion engine.

, Another object of the invention is to provide a magneto generator unithaving a novel stator and coil arrangement whereby a more durable andcompact structure is obtained, and assembly and construction of theparts of said structure are facilitated.

' Another object is to provide a dual magneto with the parts thereofarranged in a novel manner to facilitate inspection, replacement,adjustment and repair of parts while the magneto is mounted on anengine.

tures of the invention will more fully appear from the followingdetailed description when the same is read in connection with theaccompanying drawings. It is to be expressly understood, however, thatthe drawings are for the purpose of illustration only and are notintended to define the limits of the invention, reference for thislatter purpose being had primarily to the appended claims. r

In the drawings, wherein like reference characters refer to like artsthroughout the several" views,

Fig. l is a view partly in side elevation and partlyin section, withparts broken away, of one form of magneto embodying the presentinvention, with a side cover plate thereof removed;

Fig. 2 is a sectional view taken substantially along line 2--2 of Fig.1;

Fig. 3 is a view in end elevation, withparts broken-away, of the saidmagneto with an end cover plate thereof removed; and, V

Fig. A is an enlarged sectional view taken substantially along the axisof the circuit breaker cam shaft, said view showing an oil seal forrendering the compartment for the transmission gear oil-tight. v v

' An embodiment" of the invention is illustrated in the drawings, by wayof example, in the form of a magneto for energizing a dual ignitionsystem of a multi-cylinder, internal combustion engine. As shown, saidmagneto comprises a housing or casing including a main central sectionin having a top cover plate II (Fig. 2), side cover plates l2, which toether with said central section form chambers for containing circuitbreaker systems to be later described, and end cover plates l3. A plateIt is detachably secured to the lower end, as viewed in Fig. 1, ofhousing section III by bolts l5 and constitutes a support for themagneto rotor as well as means for securing the magneto to the enginecasing. For the latter purpose, plate I4 is provided with a plurality ofrecesses 16 adapted to receive bolts (not shown). Suitable thrustbearing means ll, preferably including an oil seal; are carried by saidplate to serve as a journal for the lower end of a rotor shaft it, thelatter, as shown, being centrally mounted in housing section In with theaxis thereof extending vertically. Shaft i8 is adjustably coupled to adriving member (not shown) from the engine by a suitable couplingassembly, for example, of the type shown in U. S. Patent No, 2,266,283,said assembly being secured by nut I! to the end of said shaft.

Mounted on shaft It in the lower part of main casing section It is amultiple pole magnetic rotor 20 (Fig. 2) comprising a cylindrical,axially magnetized, permanent magnet 2| and a plurality of laminated,soft iron pole shoes 22 adapt ed to cooperate in a manner well-known inthe art with laminated stator pole pieces 23 (Fig. 1). Since, intheillustrated embodiment, two ignition current generating systems areassociated with the single rotor 20, two pairs of laminated stator poles23 are provided, said pairs being alike in structure and beingsymmetrically arranged relative to the axis of'said rotor. Theright-hand set of stator poles is shown in Fig. 1 with one of i saidpoles broken away, and, as shown, each of said poles comprises avertical portion 23a embedded in or otherwise secured to the wall ofcasing section l0 adjacent the path of pole shoes 22, said verticalportion having the upper end thereof connected by an elbow 23b to ahorizontal portion 230. The horizontal portions 230 of each pair ofstator pole pieces are substantially parallel to each other and extendinto and compartments 2! for connection with the core of an ignitioncoil.

Compartments 2 are formed in both ends of the magneto housing betweencasing section In and removablecovers I2. said. compartments beingsubstantially alike in shape and adapted to contain like ,parts of thetwo current generating systems. Accordingly, only one of said systemsand the parts thereof are described in detail, it being understood thatthe other system comprises parts similar to those described, said likeparts of the two systems being symmetrically mounted relative to theaxis of the rotor and being designated by like numerals. Mounted incompartment 24 is an ignition coil II (Figs. 1 and 3) comprising theusual primary and secondary windings wound around a laminated metalliccore 25 and housed in a casing 21 of insulating material, such as moldedBakelite. The ends of core 26 are attached in any suitable manner to theends of portions No of stator members 23, thereby completing themagnetic path through the rotor and 2serving as a support for the coiland its housins Molded in said 0011 housing and extending transverselyacross the entire length of housing 21 is a metallic bar 28 (Figs. 1 and3) which is electrically connected by means also embedded in the housingstructure to the adjacent ends of the primary and secondary windingswhich it is desired to ground. The projecting ends of bar 2! are securedby bolts 2! (Figs. 1 and 3) to the magneto casing to thus effect aground connection and afford further support for the coil housing. Alsoembedded in casing 21 is a metallic rod 3| (Fig. 1) to which theinsulated terminal of the primary winding of the coil is connected andwhich has a terminal screw ll threaded therein to provide an externalterminal for said primary winding. Rod ll is also connected by a lead 32molded in casing 2'! to a contact II mounted in the upper end of saidcasing, said contact being preferably connected by a plug-in connector34 to a shielded cable N (Fig. 3) supported by and extending through asocket ll in the side of housing ll. Cable 84 may be connected to groundthrough an ignition switch (not shown).

Embedded or otherwise secured in the lower end of coil casing 21, withone face thereof exposed, is

a metallic plate 38 (Fig. 1) which is connected to the output end of thesecondary winding of coil 25. A block or housing I! of insulatingmaterial, such as molded Bakelite" is rigidly secured to housing sectionII beneath casing 21 by screws 38 and has a condenser molded therein. Ametallic rod 3! is slidably mounted in a sleeve 40 carried by said blockand-is biased into engagement with plate 36 by a spring 4|, said rodbeing electrically connected to one terminal of the condenser in saidblock. A metallic insert 42 (Fig. 3), carried at the center of adouble-ended socket 43 integrally formed with block 31, connects withthe other terminal of said condenser and is, in turn, connected througha plug-in connector 44 to a shielded cable 44, said connecter and cablebeing secured to a socket 45 in the side wall of magneto casing II andbeing guided by socket ll. Cable l4 may be connected to a distributor(not shown) of any well-known type, which is preferably mounted in aseparate housing, but may be contained in the magneto casing. In orderto render the magneto adaptable for ready use with various types ofengines, sockets for connectors 34 and ll are provided in both sides ofthe magneto casing, the ones not in use being closed by suitable means,such as caps 46.

A condenser block 41 (Fig. l) is secured to housing section "above coilhousing 21 by sets of-imetallic screws II and u, the latter of whichpartments ll formed by covers I! and housing section 10 is the circuitprimary breaker for the above-described primary circuit. said breakerbeing actuated by a compensated circuit breaker cam I2. Said cam ismounted on a shaft 53 which is drivably connected, in a novel mannermore fully described hereafter, to Mint shaft II and is adapted toperiodically open a pair of contacts I4 and BI (Fig. 1), the former ofwhich is connected to lead 50 by a metallic strip II and is movable by acam follower ll. Contact II is stationary and is connected to groundthrough the magneto casing so that said contact points are thusconnected in series with the primary winding of the ignition coil II andin shunt with the condenser in block 41. Contact points I and II "andcam follower '1 are shown a a single unit adjustably mounted by means ofa bracket ll upon a plate 50 which is, in turn, fixed to casing sectionII. Cam [2 is rotated at one-half engine crankshaft speed and isprovided with one lobe for each engine cylinder, the spacing of saidlobes being such as to compensate for the irregularity of the pistonmovements in a radial type engine.

In order to obtain accurate timing of the opening of contact points 54,5! with respect to the rotation of rotor 2|, cam 52 i coupled to shaft53 by means of an adjustable coupling, the latter comprising aninternally splined sleeve OI (Fig. 2) drivably engaging the splined end"a of shaft 53. The inner edge Of sleev 60 is provided with a pluralityof ratchet teeth 8| adapted to mesh with an equal number of ratchetteeth 82 on the adjacent face of a ring ll that is loosely mounted on anexternal surface of sleeve ID. The other or inner face of ring 03 isprovided with a plurality of ratchet teeth 84 numbering one more or lessthan teeth 6| on sleeve II and adapted to mesh tooth for tooth withratchet teeth II on the adjacent edge of cam 52, the latter beingloosely mounted on shaft 53. Th coupling assembly I0 and 63 may bereleasably held with ment of cam 52 relative to shaft ll, nut II isloosened sufllciently so that th ratchet teeth on sleeve M or cam I! canpass over the corresponding teeth on ring 63. By now angularly movingthe shaft first in one direction an amount equal to the pitch of teeth82 and then in the opposite direction an amount equal to the pitch ofteeth N, or vice versa, angular adjustments equal to the difference inthe pitch of said teeth can be eil'ected.

To drivably connect cam shaft II to rotor shaft It, a bevel gear U,keyed or otherwise secured to said cam shaft intermediate the endsthereof, meshes with a second bevel gear I! splined to the upper end ofsaid rotor shaft. Novel means are provided for mounting said shafts soas to form an oil-tight compartment ll for gear drive 81, I sealed fromchambers 24 and II and from .similarlyheld between the hub of gear '1and the portion of section It containing rotor ll. Bearing and sealingmeans 10, which journal the upper end of the rotor shaft, aredisposedbetween rotor 20 and gear 68 in fluid-tight engagement with thewall of housing section III. Said bearing and sealing means are shown inoutside view,. the same having incorporated therein the same elementshereinafter described in connection with the mounting of opposite endsof cam shaft 53.

As shown in Figs. 2 and 4, cam shaft 53 is supported in casing l at twopoints between chamber 69 and chambers 5! by means of ball bearlugs 12which are fitted into said casing. A novel combination of oil sealingmeans is provided in the vicinity of each bearing 12 for preventinleakage of oil from compartment 89 during operation of the magneto, saidmeans comprising a novel oil seal 1 i.

H, as illustrated (Fig. 4), commember or housing 13 Sealing means prisean outer cylindrical having a press lit in a central opening in plate 59through which shaft 53 passes. An inwardly extending radial flange I4 isformed on member 13 at the end thereof adjacent chamber 69 and has aninner cylindrical portion or member 15 attached thereto, the lattermember being dis posed a short radial distance from said shaft. Securedby a force fit in portion 15 to have sliding engagement with said shaftis a member 16 having an external shoulder "I1 pressed against flange14. The section of shaft 53 engaged by member I6 is preferably providedwith a reverse thread 18 which, during rotation of the shaft, tends todrive any oil trapped between said shaft and said member back in thedirection of compartment 69. To trap the oil which escapes into housing13 and prevent the flow thereof from said housing along shaft 63 intochamber 5|, particularly when shaft 53 is not rotating, a cylindricalmember 19 having a ring 80 of carbon secured in a fluid-tight manner; inthe end thereof remote from compartment '9 surrounds said shaft. Ring.is adapted to engage an abutment or shoulder rotatable with said shaft,such as the inner end of cam 52, and is pressed into fluid-tight contactwith said abutment by a plurality of springs 8| contained in housing II.As shown, springs 8i are spaced about the periphery of the shaft and oneend thereof bears against flange 14 while the other end presses againsta flange member 82 rigidly secured to member 18. An inwardly extendingflange member 88 is secured in the end of housing I! and acts to preventsprings II from ejecting cylindrical member 19 from the oil sealassembly when cam 52 or said assemblyis removed from shaft '3. To sealthe annular space between member I! and flange member 83, an annularsheet of flexible, oil-proof and oil-resistant material N is suitablysecured across said space by being clamped between flange member 82 andmember II at its inner edge and between flange member 88 and housing 13at its outer edge. A sealing action is thus obtained at both ends ofsealing means ll, insuring fluid-tightness.

As a further precaution against the escape of oil from chamber 68 alongshaft 53, a pair of oil slingers 90, iii may be mounted on said shaftfor rotation therewith, said slingers being preferably located adjacentthe inner ends of bearings 12 so as to sling oil back into said chamber.As shown in Fig. 4, sllnger 90 is shoulder 92 formed on shaft 53 and theinner race of left-hand bearing I2, while slinger II is right-handbearing II. A third oil slinger (not shown) may be mounted on the upperend of rotor shaft It as a part ofassembly 10.

Means are provided for ventilating the interior of the magneto housingand, as shown, comprise passages 93 (Fig. 2) connecting each of chambers51 with the portion of the interior of housing section III whichcontains rotor 20. Ventilating members 94 are provided for each ofcompartments 5i and 21, preferably by being connected tocovers l2 and 13for said compartments. Each of said ventilating members admits air intothe housing and is preferably provided with a suitable means, such as abaille arrangement for preventing water and foreign matter from enteringthe housing.

There is thus provided a novel dual ignition magneto unit comprising asingle rotor and two like current generating systems energized thereby,said unit including a novel oil-tight compartment for the transmissiongearing between said rotor and the circuit breaker drive shaft. The likeparts of said current generating systems are arranged in a novel mannerrelative to the rotor, the same being symmetrically disposed in relationto the axis of the rotor to provide a compact structure which can bereadily constructed, assembled, inspected and repaired. Novel means arealso provided for making the necessary electrical connections betweenthe ignition coil, condenser, circuit breaker, distributor, ground andignition switch whereby the length and number of wires within themagneto housing are greatly reduced, thereby minimizing the probabilityof failure in the ignition system due to chafing or breaking of wires.Additionally, novel means are provided for adiustably connecting acircuit breaker cam to the driving shaft therefor.

Although only a single embodiment of the invention has been illustratedand described, it is to be expressly understood that many changes,including rearrangements and design of the parts illustrated, which willnow be apparent to those skilled in the art, may be made withoutdeparting from the spirit and scope of the invention. For a definitionof the limits of the invention, reference is had primarily to theappended claims.

What is claimed is: r

1. In a magneto having a, single magnetic rotor and a pair of currentgenerating systems energized by said rotor, each of said systemscomprising an ignition coil, condensers connected to the windings ofsaid coil, and a circuit breaker,

clamped between a named compartments means for housing and mounting theabove elements of said systems whereby like parts of the latter aresymmetrically disposed relative to the axis of rotation of said rotor,said means comprising side compartments for the circuit breakersdisposed on opposite sides of a plane containing said axis andcompartments for the coils and the condensers connected thereto, saidlastbeing disposed on opposite sides of a plane containing said axis andperpendicular to said first-named plane.

2. In a magneto having a single rotor and a pair of current generatingsystems energized by said rotor, each of said systems comprising statorpoles. an ignition coil. condensers connected to posed relative to theaxis of rotation of said rotor,

said means comprising a central compartment for said rotor, compartmentsfor the circuit breakers disposed on opposite sides of said axis and aplane containing the latter, and compartments disposed on opposite sidesof a plane containing said axis and perpendicular to said first-namedplane for the coils and the condensers connected thereto, said statorpoles being mounted in said housing and extending into said last-namedcompartments.

3. In a magneto having a rotor and a pair of current generating systemsenergized by said rotor, each of said systems comprising an ignitioncoil and a circuit breaker, means for housing and mounting the aboveelements whereby like parts of said systems are symmetrically disposedrelative to the axis of rotation of said rotor, said means comprising acentral chamber for said rotor, side compartments for the circuitbreakers disposed on opposite sides of said axis and a plane containingthe latter and compartments for said ignition coils disposed on oppositesides of said axis and a plane containing said axis and perpendicular tosaid first-named plane, each of said compartments being provided with aremovable cover.

4. In a magneto having a rotor, a pair of current generating systemsenergized by said rotor, each of said systems comprising an ignitioncoil and a, circuit breaker, drive means operatively connecting theoperating means for said circuit breakers to said rotor, and means forhousing the foregoing elements comprising a central chamber for saidrotor, a. side compartment for each of said circuit breakers, acompartment for each of said ignition coils, and a substantiallyliquidtight compartment disposed between said side compartments forcontaining said drive means, each of said compartments having aremovable cover.

5. In a magneto having a rotor, a pair of current generating systemsenergized by said rotor, each of. said systems comprising an ignitioncoil and a circuit breaker, drive means operatively connecting theoperating means for said circuit breakers to said rotor, and means formounting and housing the like parts of said systems whereby said partsare symmetrically disposed relative to the rotor axis with the coils andcircuit breakers on different sides of said axis, said last-named meansincluding a central compartment for said rotor, a side compartment foreach of said circuit breakers, and a substantially liquid-tightcompartment disposed between said side compartments and above saidcentral compartment for containing said drive means.

6. In a magneto having a dual current generating system,, a singlerotor, a pair of circuit breakers, a housing having a centralcompartment for saidrotor and a side compartment for each of saidcircuit breakers, a common drive shaft with operating means thereon forsaid circuit breakers, power transmitting means connecting said driveshaft to said rotor, and a substantially liquid-tight chamber disposedbetween said side compartments and adjacent one end of said centralcompartment for containing said transmitting means.

7. A magneto having a dual current generating system, a housing, amagnetic rotor mounted therein, a shaft rotatably mounted in saidhousing, means for drivably connecting said rotor and shaft, asubstantially liquid-tight chamber containing said connecting means, oneend of the shaft of said motor extending into said chamber and saidfirst-named shaft extending through and having both ends thereofprojecting out of said chamber, and a pair of circuit breaker .camsmounted on said first-named shaft at opposite ends thereof.

' 8. In a magneto having a rotor and an ignition coil, a central casingfor mounting the rotor, a chamber for containing the ignition coil, apair of laminated stator poles, each of said poles having one endportion thereof mounted in said casing to be adjacent said rotor andwith the laminations thereof extending longitudinally in a directionparallel to the rotor axis and the other end portion having thelaminations thereof extending longitudinally substantiallyperpendicularly from said first-named end portion into said chamber toconnect with one end of the core of said ignition coil.

9. In a magneto having a rotor and an ignition coil, a pair of statorpoles, each of said poles having an end portion thereof mounted adjacentsaid rotor and extending longitudinally in a direction parallel to therotor axis and the other end portion extending longitudinallysubstantially perpendicularly from the first-named end portion toconnect with one end of the core of said ignition coil.

10. In a magneto having a housing, an ignition coil comprising primaryand secondary windings, an insulating casing for said coil, common meansfor supporting said casing and grounding one end of each of saidwindings, a metallic strip molded in the upper end of said casing andconnecting with the ungrounded end of the primary winding, an exposedterminal partially embedded in the upper end of said casing andconnecting with said strip, a socket in said housing for supporting anignition switch cable for contact with said terminal, a second terminalembedded in the upper end of said casing and connecting with said strip,a condenser supported by said housing above and adlacent to said casing,

means for connecting said condenser to said second terminal, a metalliccontact embedded in the lower end of said casing and connecting with theungrounded end of said secondary winding, a condenser block secured tosaid housing and disposed below said casing, and means slidablyconnecting the condenser in said block to said metallic contact.

11. In a magneto having a metallic housing, an ignition coil comprisingprimary and secondary windings, an insulating casing for said coil. ametallic member molded in said casing and connected to one end of eachof said windings. said member being secured to said housing to supportsaid coil and ground said windings, a metallic strip completely embeddedin said casing and connecting with the ungrounded end of said primarywinding, a pair of terminals connected to said strip, socket means insaid housing adapted to hold-an ignition switch cable in contact withone of said terminals, a condenser, a circuit breaker, and meansconnecting said condenser and circuit breaker to the other of saidterminals.

12. In a magneto, a housing, an ignition coil comprising primary andsecondary windings, an insulating casing for said coil, common means forsupporting said coil and grounding one end of the primary windingthereof, a metallic strip embedded in said casing and connecting withthe ungrounded end of the primary winding, an exposed terminal embeddedin said casing and connecting with said strip, a socket in said housingfor supporting a cable for contact with said terminal, a second terminalembedded in said casing and connecting with said strip, a condensersupported by said housing adjacent said terminals, and means forconnecting said condenser to said second terminal.

13. In a magneto, an ignition coil comprising primary and secondarywindings, an insulating casing for said coil, means for grounding oneend of said secondary winding, a metallic plate embedded in said casingwith one face thereof exposed, said plate being connected to theungrounded end of said secondary winding, and a condenser block mountedadjacent said casing, said block housing a condenser, a spring-pressedcontact connected to one terminal of said condenser, said contact beingbiased into engagement with said plate, and a metallic member connectedto the other terminal of said condenser, a socket being formed in saidblock for receiving a cable adapted to connect with said metallicmember.

14. In apparatus of the class described, a retatable shaft, a circuitbreaker cam loosely mounted on said shaft and surrounding a reducedportion thereof, a sleeve drivably connected to said reduced portion, aring loosely mounted on said sleeve within said cam, said ring havingunequal numbers of ratchet teeth on opposite faces thereof cooperatingwith ratchet teeth on said sleeve and cam, and means threaded onto saidshaft for holding said ratchet teeth in driving engagement, whereby saidcam is drivably connected to said shaft for angular adjustment relativethereto. I

15. A magneto comprising housing means, a magnetic rotor rotatablymounted in a central portion of said housing means, the latter having aplurality of removable covers forming four compartments spaced at 90degree intervals around the axis of rotation of said rotor, an ignitioncoil in each of two oppositely disposed compartments having the coresthereof extending at right angles to a plane containing said axis,stator means for operatively magnetically connecting said cores and saidrotor, a condenser mounted at one side of each of said coils andconnected to the secondary winding thereof, said condensers beingmounted in corresponding parts of said last-mentioned compartments, acondenser mounted at the other side of each of said coils and connectedto the primary winding thereof, said last named condensers being mountedin corresponding parts of said last named compartments, circuit breakermeans in each of the other oppositely disposed compartments, meansconnecting each of said circuit breaker means to one of said last namedcondensers and one of said coils, cam means on opposite ends of a shaftextending at right angles to said axis for actuating said circuitbreaker means, and means in a substantially liquid-tight compartment ofsaid housing means for drivably connecting said shaft and rotor.

l6. In a magneto, a magnetic flux conducting rotor, a coil with ametallic corehaving the longitudinal axis thereof in a planeperpendicular to the axis of rotation of said rotor, and a pair oflaminated stator poles, each comprising a plurality of elongatedmetallic straps, one end of each of said poles being adjacent said rotorand having the laminations thereof extending longitudinally in adirection parallel to said rotor axis and the other end of each polebeing operatively connected with said core and having the laminationsthereof extending longitudinally in a direction parallel t said plane.

17. In a magneto, a magnetic flux conducting rotor, a coil having ametallic core mounted at one side of said rotor, and means formagnetically connecting said rotor and core comprising a pair oflaminated stator poles each having a bend therein dividing the same intotwo end portions extending at substantially right angles to each other,one end portion of each pole being adjacent said rotor with thelaminations thereof extending longitudinally in a direction parallel tothe axis of rotation of said rotor.

18. In apparatus of the class described, a rotatable shaft, an elementsuch as a circuit breaker cam loosely mounted on said shaft, a sleevedrivably connected to said shaft, a, ring loosely mounted on saidsleeve, said ring having unequal numbers of ratchet teeth on oppositefaces thereof cooperating with like numbers of ratchet teeth on saidsleeve and element, and means threaded onto said shaft for holding saidratchet teeth in driving engagement, whereby said element is drivablyconnected to said shaft for angular adjustment relative thereto.

JAKOB R. FREI.

